Medical devices are typically operated inside of a health care environment in close proximity to patients, other electrical devices and other objects made of conductive material. As a result, there is a risk of unwanted transfer of electrical energy and signal interference between such devices and such objects while providing health care to a patient.
For example, an electrocardiogram (ECG) monitoring apparatus receives and processes electrocardiogram (ECG) signals generated by a circulatory system of a person. The apparatus typically includes a plurality of ECG (patient contact) electrodes that are each electrically connected to a lead wire and that are each configured to make physical contact with the person being monitored. The ECG electrodes and lead wires are also configured to receive and relay ECG signals generated by the person to components of the ECG monitoring apparatus that process the ECG signals.
In some circumstances, the person may be experiencing some sort of cardiovascular instability, such as ventricular fibrillation. Ventricular fibrillation is a disturbance of electrical activity within a ventricular muscle of the heart. In order to arrest ventricular fibrillation, the patient may be administered a defibrillation shock via defibrillating device. In some circumstances, the patient may be administered the defibrillation shock while the patient is being monitored by an ECG monitoring apparatus. The defibrillation shock can create a voltage surge that can unintentionally conduct (travel) through one or more of the ECG contact electrodes and/or lead wires and cause interference with the communication of data between the ECG electrode and components of the ECG monitoring apparatus that process the ECG signals. Further, the defibrillation shock not only interferes with the communication of data, but if not galvanically isolated, the defibrillation shock could also travel through the device and harm the user.